package com.freemypay.test.并发.共享受限资源.原子性和易变性;

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;

/**
 * 测试SerialNumberGenerator 
 * @author yesixian
 * @date 2018年5月16日
 */
public class SerialNumberChecker {
	private static final int SIZE = 10;
	private static CircularSet serials = new CircularSet(100);
	private static ExecutorService exec = Executors.newCachedThreadPool();

	static class SerialChecker implements Runnable {

		/**
		 * 貌似不会有重复的值
		 */
		@Override
		public void run() {
			while (true) {
				int serial = SerialNumberGenerator.nextSerialNumber();
				if (serials.contain(serial)) {
					System.out.println("Duplicate: " + serial);
					System.exit(0);
				}
				serials.add(serial);
			}

		}

	}
	
	public static void main(String[] args) throws NumberFormatException, InterruptedException {
		for (int i = 0; i < SIZE; i++) {
			exec.execute(new SerialChecker());
		}
		if(args.length > 0) {
			TimeUnit.SECONDS.sleep(new Integer(args[0]));
			System.out.println("no duplicates detected");
			System.exit(0);
		}
	}
}

class CircularSet {
	private int[] array;
	private int len;
	private int index = 0;

	public CircularSet(int size) {
		array = new int[size];
		len = size;
		for (int i = 0; i < size; i++) {
			array[i] = -1;
		}
	}

	public synchronized void add(int i) {
		array[index] = i;
		index = ++index % len;
		System.out.println("index: " + index + " serial: " + i);
	}

	public synchronized boolean contain(int val) {
		for (int i = 0; i < len; i++) {
			if (array[i] == val) {
				return true;
			}
		}
		return false;
	}
}
